The air intake streams of motorized devices such as vehicles, construction equipment, and powered tools often include particulate material. In power tool applications in particular, particulate material may include high concentrations of dust and debris from the workpiece. The particulate material, should it reach the internal operating mechanism, can cause substantial damage to the device. It is therefore beneficial to reduce the level of particulate material in the airflow at a point upstream from the operating mechanism (e.g., the motor or other equipment).
Dust extraction and ejection mechanisms are typically utilized to separate particulate material from the airstream. U.S. Pat. No. 8,348,727 assigned to Black & Decker Inc. discloses a power tool system in which a dust extraction system (i.e., a particle dispersion assembly) includes a baffle and a passive fan disposed to deflect particles from airflow. The baffle in that system includes angularly-positioned slats that direct the travel direction of the airflow angularly with respect to the passive fan. The airflow causes the passive fan blades to spin, which deflects the travel direction of the airflow in multiple directions to remove and disperse particles from the airflow. This arrangement is effective in separating dust and debris from airflow in tools such as large angle grinders. However, for smaller hand held power tools such as small angle grinders, the passive fan of the dust ejection system occupies too much space and requires too much girth be used effectively.
It would be desirable to provide an airflow arrangement in which the dust ejection system does not include a separate fan but still provides high efficiency dust extraction and ejection system.